In the formation of a semiconductor wafer, integrated circuit devices such as transistors are first formed at the surface of a semiconductor substrate. Interconnect structures are then formed over the semiconductor substrate and the integrated circuit devices. Electrical connectors such as metal bumps are formed on the surface of the semiconductor wafer to electrically connect to the integrated circuit devices. The semiconductor wafer is sawed into a plurality of semiconductor chips.
Packaging the semiconductor chips may be performed through reflow processes. During the reflow processes, the solder regions between the electrical connectors of the semiconductor chips are reflowed to bond the semiconductor chips to other package components such as device dies, interposers, package substrates, or the like. The solder regions are molten in the reflow processes. The shapes and the profiles of the molten solder regions are difficult to control, however. This may cause problems such as bridging, and hence deteriorations of the bonding quality or the yield loss.